Bill Mantlo was a lawyer and prolific writer of comic books for Marvel and (to a lesser extent) DC, for over 20 years.

During his career he wrote issues of nearly every title Marvel published, featuring nearly every character (including several which he created himself). His more notable work includeed stints as regular writer on Incredible Hulk, Spectacular Spider-man , Cloak and Dagger (comics) (whom he created) and Alpha Flight. He is probably best remembered for the work he did on two licensed toy properties whose adventures occurred in the Marvel Universe, Micronauts and Rom (Spaceknight).

His work for DC included the Invasion miniseries.

In the late 1980s, shortly after finishing Invasion, he left comics to focus on his legal career as a public defender.

In 1995, Mantlo was struck by a car while rollerblading. He suffered severe head trauma and spent over a year in a coma; he has since been institutionalized.